Prenatal Exposure to Ozone Linked to Reduced Birth Weight
This study investigated the effects of air pollutants on birth weight among term infants who were born in California during 1975-1987 and who participated in the Children’s Health Study.
Birth certificates provided maternal reproductive history and residence at time of birth. Information on sociodemographic factors and maternal smoking during pregnancy were collected by questionnaire. Monthly average air pollutant levels were interpolated from monitors to the zip code of the mother’s residence at childbirth.
The researchers observed an association between lower birth weight and intrauterine growth retardation with ozone concentrations. Second- and third-trimester ozone levels were most strongly associated with deficits in birth weight, followed by carbon monoxide exposures during the first trimester. They reported a clear pattern of increasing deficits in birth weight with increasing levels of ozone for 24-hour ozone levels above 30 ppb.
Although the differences in birth weight were small on average, those in the highest ozone exposure group had deficits of a magnitude equivalent to those observed after exposure to cigarette smoke.
“Because exposures to the levels of ambient air pollutants observed in this study are common, and fetal growth is an important determinant for childhood and adult morbidity and mortality, or findings are likely to have important public health and regulatory implications,” conclude the researchers.
Salam MT, Millstein J, Li Y-F, Lurmann FW, Margolis HG, Gilliland FD. Birth Outcomes and Prenatal Exposure to Ozone, Carbon Monoxide, and Particulate Matter: Results from the Children’s Health Study. Environ Health Perspec 2005; 113:1638-1644.
For a copy of the article click here.
